Question 17N.3.HL.TZ0.20
| Date | November 2017 | Marks available | [Maximum mark: 6] | Reference code | 17N.3.HL.TZ0.20 |
| Level | HL | Paper | 3 | Time zone | TZ0 |
| Command term | Describe, Outline, State | Question number | 20 | Adapted from | N/A |
Thyroxin is a hormone produced in the thyroid gland. State one function of thyroxin.
[1]
a. regulates the «basal» metabolic rate/BMR
b. controls body temperature
[Max 1 Mark]
The action of thyroxin is similar to steroid hormones. Describe the action of steroid hormones.
[3]
a. steroid hormone passes through cell/plasma membrane
b. binds to receptor «proteins» in cytoplasm
c. receptor–hormone complex travels to nucleus
d. binds to DNA/chromatin
e. promotes/inhibits the transcription of specific genes
f. codes for/produces specific proteins
[Max 3 Marks]
The World Health Organization recommends that the iodine intake should be supplemented in pregnant women due to their increased requirements. Outline the need for iodine supplementation.
[2]
a. iodine is an essential nutrient/cannot be synthesized by the body
b. iodine is required for thyroid hormones/thyroxin production
c. some areas in the world have iodine deficient soil/low iodine in their diet
d. supplementation will reduce stunted growth and mental development/cretinism in babies born to mothers associated with thyroid deficiency
e. thyroid deficiency will lead to health problems
[Max 2 Marks]